This year's Longitude Prize is focused on the growing problem of antibiotic resistant bacteria. They've put together a nice image, shown below, which showcases what they term 'the ten most dangerous antibiotic resistant bacteria'. You can read more detail on each of them here: http://www.nesta.org.uk/news/antibiotic-resistant-bacteria
Vorticella: a colony of single-cell ciliates; the sausage-shaped nuclei are orange, cilia - blue. Some smaller protozoans are attached to the stem. Taken with laser scanning confocal microscope, 100x mag. By Igor Siwanowics aka Blepharopsis.